Not Applicable.
Not Applicable.
The present invention relates to a spring balance assembly for a sash window. More specifically, the present invention relates to a spring balance assembly with stacked or tandem coil springs that increases the operating range and egress of the sash window.
Sash windows disposed within a master frame are quite common. Generally, the master frame includes a pair of opposed vertical guide rails, an upper horizontal member or header, and a lower horizontal member or base. The guide rails are designed to slidingly guide at least one sash window within the master frame. For double hung sash windows, a common window configuration, the guide rails define an elongated channel. To counterbalance the sash window during movement of the window, a spring balance assembly is affixed to the master frame in the elongated channel and connected to the sash window. Due to its structural configuration, conventional spring balance assemblies are generally positioned below the midpoint of the master frame. The spring balance assemblies must be affixed below the midpoint because their structure will interfere with the hardware mounted to the sash window during the sliding movement of the sash window. Specifically, the structure of the spring balance assembly, for example the plastic plate that houses the coil springs, will make contact with a latch bolt of a tilt-latch mounted on the sash window during movement of the sash window if the spring balance assembly is affixed at or above the midpoint of the master frame. Accordingly, to prevent contact and interference during the sliding movement of the sash window, the spring balance assembly must be mounted below the midpoint of the master frame. As a result, the operating range or lift height of the sash window is diminished thereby reducing the egress through the sash window.
In addition, conventional spring balance assemblies exhibit a limitation regarding the manner in which the coil springs are connected to the pivot brake assembly. Typically, a threaded fastener is utilized to connect the coil springs to a portion of a pivot brake assembly that pivotally supports the sash window. The fastener is inserted through an opening in the lower portion of the coil spring and received by an aperture of the pivot brake assembly. The use of a threaded fastener presents problems when the coil springs have different sizes, primarily different widths, because the openings in the coil springs are not aligned when the coil springs overlap to connect the springs to the same portion of the pivot brake assembly. Improper alignment of the coil springs produces undesirable noise during the operation of the coil springs and the spring balance assembly. In addition, improper alignment introduces a horizontal force component to the movement of the coil springs which negatively affects the performance and durability of the spring balance assembly.
An example of a spring balance assembly susceptible to the limitations identified above is found in U.S. Pat. No. 4,961,247 to Leitzel et al. Referring to FIG. 4 therein, the first balance assembly 1A is positioned in the elongated channel 35 of guide rail 34 a significant distance from the junction point or jamb head 36. In addition, the second balance assembly 1B is positioned in the elongated channel 37 of guide rail 32 above the first balance assembly 1A but still a considerable distance from the jamb head 36. As shown in FIGS. 1-3, the spring holder 6 has a generally linear configuration that requires the balance assemblies 1A,B to be positioned below the midpoint of the channel 35, 37. Consequently, the operating range of the balance assemblies 1A,B and the sash window are limited.
Therefore, there is a need for a spring balance assembly that can be affixed to the master frame at a higher vertical position of the master frame to increase the operating range and egress characteristics of the sash window. In addition, there is a need for a spring balance assembly having an interface means for securing different sized coil springs to the pivot brake assembly while ensuring the proper alignment of the coil springs. The present invention is provided to solve these and other deficiencies.
The present invention relates to a spring balance assembly for use with a sash window. The spring balance assembly comprises a plate, a pivot brake assembly, a clip, a first coil spring, and a second coil spring. The plate has a first portion, a second portion, and a transition wall. The transition wall is positioned between the first and second portions thereby creating a step or ledge between the portions. The stepped or staggered configuration of the plate enables the spring balance assembly to accommodate the hardware of the sash window during sliding movement of the window thereby allowing the spring balance assembly to be positioned at or above a midpoint of the master frame. As a result, the lift height and operating range of the sash window is increased and egress through the window is enhanced.
The spring balance assembly comprises a plate having a first portion, a second portion, and a transition portion or wall. The transition wall is positioned between the first and second portions thereby creating a step or ledge between the portions. A top wall extends from an upper edge of the first portion and towards an inner surface of the master frame. The plate has a length, thickness, and width which can be varied depending upon the design parameters of the spring balance assembly.
In accord with the invention, a first spool adapted to support a first coil spring extends generally perpendicular from the first portion. Similarly, a second spool adapted to support a second coil spring extends generally perpendicular from the second portion. The first and second spools rotatably support the first and second springs but do not bind or inhibit the rotation of the springs. Preferably, each spool is tubular thereby defining an elongated passageway. A fastener is inserted into one or both passageways to secure the spring balance assembly to the master frame within the channel. A first rotatable drum can be positioned between the first spool and the first spring. A second rotatable drum can be positioned between the second spool and the second spring.
The first spring has an upper or coiled end that is coiled about the first spool, and a lower or free end that is connected to a portion of a pivot brake assembly. Similarly, the second spring has an upper or coiled end that is coiled about the second spool, and a lower end that is connected to a portion of the pivot brake assembly. The pivot brake assembly is operably connected to a lower portion of the sash window near the base rail. When the pivot brake assembly is coupled to the sash window the spring balance assembly counterbalances the weight of the sash window wherein the first and second springs exert a generally upward force on the sash window.
The spring balance assembly further includes an interface means or clip. In general terms, the clip is adapted to connect the first spring and the second spring to the pivot brake assembly. The clip has a first attaching element adapted to engage an opening in the free end of the first spring and a second attaching element adapted to engage an opening of the second spring. An aperture is positioned in a depending region of the clip and generally between the first and second attaching elements. A portion of the clip is received by a recess in a first wall of the pivot brake assembly. A fastener is employed to secure the clip to the pivot brake assembly. The fastener can be a screw, rivet, or any elongated structure capable of securing the clip, the first or second springs, and the pivot brake assembly.
In further accord with the invention, the spring balance assembly has a cavity proximate the first portion of the plate. The cavity has a generally rectangular configuration resulting from the stepped or staggered configuration of the plate. The cavity is adapted to provide clearance for the nose portion of the bolt of the latch bolt hardware mounted to the sash window. The spring balance assembly is affixed to the master frame with a portion of the assembly positioned above the midpoint of the master frame. When the spring balance assembly is affixed at or above the midpoint, the cavity receives the nose portion of the bolt. When the sash window is moved in a generally vertical and upward direction from the closed position to an open position, the nose of the bolt moves from a lower portion of the cavity through an upper portion of the cavity. In this manner and in contrast to conventional devices, the cavity accommodates the sliding movement of the nose portion of the bolt. Similarly, the cavity further accommodates the sliding movement of the nose of the bolt 21 when the sash window is moved from the open position to the closed position. The accommodation of the bolt permits the spring balance assembly to be affixed to the master frame with a portion above the midpoint of the master frame. Thus, the position of the spring balance assembly affects the operating range of the sash window.
In another embodiment shown, the spring balance assembly comprises a plate with a first portion, a second portion, and a transition wall. The transition wall is positioned between the first and second portions thereby creating a step or ledge between the portions. A top wall extends from a top edge of the first portion and towards an inner surface of the master frame. In this embodiment, the clip is omitted from the spring balance assembly and as a result, the first spring and second spring are connected directly to the pivot brake assembly to define an assembled position. In the assembled position, the first spring is connected to the second wall of the pivot brake assembly, and the second spring is connected to the first wall of the pivot brake assembly. The first and second springs rotate in opposite directions. For example, when the first spring rotates in a counter-clockwise direction, the second spring rotates in a clockwise direction.
Other features and advantages of the invention will be apparent from the following specification taken in conjunction with the following drawings.